Injuries caused by sharp medical devices are common with an estimated 400,000 to 800,000 American healthcare workers injured each year. Injured healthcare workers are at risk for blood-borne viral illnesses, including hepatitis B and C, HIV infection and other less common diseases. The direct medical costs of evaluating and treating sharps-related injuries is approximately $500 million annually. Despite the recent adoption of safer medical devices, the risk of sharps-related injury remains unacceptably high. Relatively little is known about potentially preventable transient etiologic factors that immediately precede these injuries. In this revised application we propose to conduct a case-crossover study of 1,000 healthcare workers who sustain a sharps-related injury recruited from six hospitals in Boston and Baltimore. We will evaluate risk factors in the following domains: 1) worker-related factors such as rushing, fatigue, distraction and feelings of anger 2) procedure-related factors such as uncommon, unusual or emergency procedures 3) workplace-related factors such as working short-staffed, overtime or while on-call and 4) device-related factors such as use of an unusual or malfunctioning device. We will also evaluate differences in the risks between workers with differing characteristics such as age, gender, profession, and history of prior sharps-related injuries. The effect of risk factors in continuous exposure settings such as operating rooms and intermittent exposure settings such as inpatient units and outpatient clinics will be evaluated. In a pilot study 90 healthcare workers were interviewed by telephone. Forty were nurses and 28 were trainees. Twenty were injured while scrubbed in an operating room or procedure suite and 15 had known exposures to HIV or hepatitis C. Among our preliminary findings, an increased risk of sharps-related injury was associated with rushing (RR 5.1, 95% Cl 3.0-8.7), anger (RR 4.7, 95% Cl 1.9-12.2), distraction (RR 8.6, 95% Cl 4.3-17.2), and multiple passes (RR 3.1, 95% Cl 1.6-3.5). There were trends toward higher risk while working short staffed, and among surgeons working in a bloody operative field. Trends toward lower risk were seen with emergency procedures, and while being taught.Successful completion of this study may identify modifiable risk factors for hospital-acquired sharps-related injuries. This knowledge may lead to individual and systems level risk-reduction interventions.